Embolic protection device

ABSTRACT

The embolic protection device ( 10 ) has an expandable tubular structure supporting a filter mesh material ( 12 ). The embolic protection device is compressed to a small diameter for insertion into a patient&#39;s aorta, then expanded within the aorta with the filter mesh material positioned to allow blood to enter sidebranch vessels connected to the aorta and to prevent embolic material from entering the sidebranch vessels. The filter mesh material may be configured with waves or undulations ( 26 ) for increased surface area and/or with two layers of mesh material to provide additional protection against embolization and to prevent inadvertent occlusion of the sidebranch vessels.

CROSS REFERENCE TO OTHER APPLICATIONS

[0001] The present application claims priority of U.S. ProvisionalPatent Application 60/406,492, filed on Aug. 27, 2002.

FIELD OF THE INVENTION

[0002] The present invention relates to apparatus and methods forproviding embolic protection to a patient's aortic arch vessels duringcardiac surgery and interventional cardiology procedures.

BACKGROUND OF THE INVENTION

[0003] Cerebral embolism is a known complication of cardiac surgery,cardiopulmonary bypass and catheter-based interventional cardiology andelectrophysiology procedures. Embolic particles, which may includethrombus, atheroma and lipids, may become dislodged by surgical orcatheter manipulations and enter the bloodstream, embolizing in thebrain or other vital organs downstream. Cerebral embolism can lead toneuropsychological deficits, stroke and even death. Prevention ofcerebral embolism would benefit patients and improve the outcome ofthese procedures.

[0004] Previous devices for preventing cerebral embolism are describedin the following U.S. patents and patent applications, which are herebyincorporated by reference: U.S. Pat. No. 6,371,935 Aortic catheter withflow divider and methods for preventing cerebral embolization, U.S. Pat.No. 6,361,545 Perfusion filter catheter, U.S. Pat. No. 6,254,563Perfusion shunt apparatus and method, U.S. Pat. No. 6,139,517 Perfusionshunt apparatus and method, U.S. Pat. No. 6,537,297 Methods ofprotecting a patient from embolization during surgery, U.S. Pat. No.6,499,487 Implantable cerebral protection device and methods of use,U.S. Pat. No. 5,769,816 Cannula with associated filter, US20030100940A1Implantable intraluminal protector device and method of using same forstabilizing atheromas.

SUMMARY OF THE INVENTION

[0005] The present invention takes the form of apparatus and methods forproviding embolic protection to a patient's aortic arch vessels duringcardiac surgery and interventional cardiology and electrophysiologyprocedures. Embolic particles in the aortic blood flow are preventedfrom entering the aortic arch vessels and carotid arteries that lead tothe brain. The apparatus and methods of the present invention can alsobe used for embolic protection of other organ systems, such as the renalsystem.

[0006] In one embodiment, a stent-like embolic protection device isconstructed of a self-expanding tubular mesh that may be woven out ofwires or fibers or formed from a tube or sheet. The embolic protectiondevice is compressed to a small diameter and inserted into a deliverytube or catheter, which is introduced via a peripheral artery or anaortotomy and advanced into the aortic arch. Once in place, the deliverytube is withdrawn to allow the device to expand similar to aself-expanding stent. The mesh of the device covers the ostia of thearch vessels, allowing blood to enter, but preventing potential embolifrom entering the aortic arch vessels and carotid arteries. The deviceconforms closely to the walls of the aorta so that it will not interferewith performing cardiac surgery or interventional cardiology procedures.The embolic protection device may be collapsed and withdrawn from theaorta after the procedure or it may be left in the aorta for long-termembolic protection.

[0007] In another embodiment, the embolic protection device may be madewith a flat panel of fine mesh textile fabric that is supported on awire frame or the like. The panel of fine mesh fabric is held in placeover the aortic arch vessels by the wire frame to filter out potentialemboli. Being made of fabric, the device is free to conform to the ostiaof the arch vessels to allow more surface area for blood flow comparedto a flat panel. The wire frame may be attached to a handle or cannulafor insertion through an aortotomy or to a catheter for peripheralartery insertion. In addition, the wire frame may include one or morewire hoops or a stent-like tubular structure for supporting the embolicprotection device within the aortic arch.

[0008] Additional features are described which may be used with eitherembodiment of the embolic protection device. An embolic protectiondevice is described with waves or undulations to provide more surfacearea for filtering out potential emboli and to prevent inadvertentocclusion of the arch vessels. Another embolic protection device isdescribed with two layers of mesh material to provide additionalprotection against embolization and to prevent inadvertent occlusion ofthe arch vessels. An embolic protection device is described with aninflatable toroidal balloon for supporting the filter mesh materialwithin the aorta. The embolic protection device or a portion of it maybe coated with an antithrombogenic coating to reduce the formation ofclots that could become potential emboli.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 shows a stent-like embolic protection device deployedwithin a patient's aortic arch for protecting the aortic arch vesselsand carotid arteries from potential emboli.

[0010]FIG. 2 shows a stent-like embolic protection device with waves orundulations.

[0011]FIG. 3 shows a cut-away view of a stent-like embolic protectiondevice with two layers of mesh material.

[0012]FIG. 4 shows an alternative embodiment of an embolic protectiondevice.

[0013]FIG. 5 shows another alternative embodiment of an embolicprotection device.

DETAILED DESCRIPTION OF THE INVENTION

[0014]FIG. 1 shows a stent-like embolic protection device 10 deployedwithin a patient's aortic arch for protecting the aortic arch vesselsand carotid arteries from potential emboli. The embolic protectiondevice 10 is made of a resilient material, either a polymer or a metal(e.g. Nitinol) or a combination of materials. The device 10 may be wovenout of wires or fibers to form a tubular mesh structure 12 or byslitting and expanding a tube or sheet. Alternatively, the device 10 maybe constructed with a tubular mesh structure 12 made of a flexibletextile mesh with one or more wire hoops or a stent-like tubularstructure for supporting the tubular mesh structure 12 within the aorticarch. The device 10 is compressible to a small diameter for insertioninto the aorta via peripheral artery access or through an aortotomy. Thedevice 10 is preferably self-expanding and, when expanded, has agenerally tubular shape that conforms to the diameter and curvature ofthe aortic arch.

[0015] The embolic protection device 10 is compressed to a smalldiameter and inserted into a delivery tube or catheter 14. The deliverytube is introduced via a peripheral artery or an aortotomy and advancedinto the aortic arch. Once in place, the delivery tube 14 is withdrawnto allow the device 10 to expand similar to a self-expanding stent. Themesh 12 of the device covers the ostia of the arch vessels, allowingblood to enter, but preventing potential emboli from entering the aorticarch vessels and carotid arteries. The device 10 conforms closely to thewalls of the aorta so that it will not interfere with performing cardiacsurgery or catheter-based interventional cardiology or electrophysiologyprocedures.

[0016] Alternatively, the embolic protection device 10 may beballoon-expandable. In this case, the embolic protection device 10 wouldbe crimped or compressed onto an expandable balloon mounted on acatheter. The catheter is introduced into the aortic arch and theballoon is expanded to deploy the embolic protection device 10 in theaorta. Other volume expanding mechanisms, such as a mechanical expander,may be used in lieu of an expandable balloon.

[0017] After the procedure is completed, the embolic protection device10 may be compressed and withdrawn from the aorta. Alternatively, thedevice 10 may be left in the aorta for long-term embolic protection. Thedevice 10 may be compressed using one or more drawstrings 16 thatencircle the device. The drawstrings 16 are pulled to compress thedevice and the device is withdrawn into the delivery tube 14 forremoval. Alternatively, the embolic protection device 10 may bestretched longitudinal with the aid of a catheter, which will cause thediameter of the device to contract. Alternatively, the embolicprotection device 10 may use a magnetic mechanism for compressing thedevice for removal. Multiple magnets 18 are arranged around theperiphery of the device 10. After the procedure is completed, a catheter20 carrying one or more strong magnets 22 is inserted through the lumenof the device 10 to compress the device around the catheter for removal.

[0018]FIG. 2 shows a stent-like embolic protection device 24 with wavesor undulations 26 in the tubular mesh structure 28. The waves orundulations 26 in the embolic protection device 24 provide more surfacearea for filtering out potential emboli and prevents inadvertentocclusion of the arch vessels. This feature may be combined with any ofthe other embodiments and features of the invention described herein.

[0019]FIG. 3 shows a cut-away view of a stent-like embolic protectiondevice 30 wherein the tubular mesh structure 32 is constructed with twolayers of mesh material. The embolic protection device 30 preferably hasan outer layer 34 of fine mesh material and an inner layer 36 of coarsemesh material. The outer layer 34 is shown cut away so that the innerlayer 36 is visible. One or both layers of the device 30 may beself-expanding. For example, the outer layer 34 may be made of a finemesh textile fabric, while the inner layer 36 is made with aself-expanding wire mesh structure. The two-layer structure providesadditional protection against embolization and prevents the fine mesh ofthe outer layer 34 from becoming clogged with large emboli. Also,because blood can flow between the inner and outer layers of the device,all of the arch vessels will continue to receive blood flow even if theinner layer in front of one or more of the vessels becomes clogged. Thisfeature may be combined with any of the other embodiments and featuresof the invention described herein. For example, one or both layers ofthe two-layer construction may be made with waves or undulations asdescribed above in connection with FIG. 2.

[0020]FIG. 4 shows an alternative embodiment of an embolic protectiondevice 40. In this embodiment, the embolic protection device 40 may bemade with a panel of fine mesh textile fabric 42 that is supported on awire frame 44 or the like. The panel of fine mesh fabric 42 is held inplace over the aortic arch vessels by the wire frame 44 to filter outpotential emboli. Being made of fabric, the mesh panel 42 is free toconform to the ostia of the arch vessels to allow more surface area forblood flow compared to a totally flat panel.

[0021] The wire frame 44 may be attached to a handle or cannula 46 forinsertion through an aortotomy or to a catheter 48 for peripheral arteryinsertion. Alternatively or in addition, the wire frame 44 may includeone or more wire hoops 50 or a stent-like tubular structure forsupporting the embolic protection device 40 within the aortic arch. Thisembodiment and/or its features may be combined with any of the otherembodiments and features of the invention described herein. For example,the mesh panel 42 may be made with waves or undulations as describedabove in connection with FIG. 2 and/or with a two-layer construction asdescribed in connection with FIG. 3. As a further example, the handle,cannula 46 or catheter 48 for insertion of the embolic protection device40 described in connection with FIG. 4 may also be combined with any ofthe embolic protection devices described in connection with FIGS. 1-3and 5.

[0022]FIG. 5 shows another alternative embodiment of an embolicprotection device 52. An inflatable toroidal balloon 54 supports theupstream end of a tubular mesh structure 56. The toroidal balloon 54 isinflated and deflated through a catheter 58 having an inflation lumenand, optionally, a guidewire lumen. The tubular mesh structure 56 may bea self-expanding structure woven of wires or fibers or it may be aflexible textile mesh. Optionally, one or more wire hoops 60 or the likemay be used to support the tubular mesh structure 56 within the patent'saorta. Alternatively, one or more additional inflatable toroidalballoons 54 may be used in place of the optional wire hoops 60 tosupport the tubular mesh structure 56. The features of this embodimentmay be combined with any of the other embodiments and features of theinvention described herein. For example, one or more inflatable toroidalballoons 54 may be combined with the embolic protection devicesdescribed in connection with FIGS. 1-3 for supporting a tubular meshstructure or panel of mesh material.

[0023] The entire embolic protection device or a portion of it may becoated with an antithrombogenic coating, for example a bonded heparincoating, to reduce the formation of clots that could become potentialemboli. Alternatively or in addition, the embolic protection device or aportion of it may have a drug-eluting coating containing ananti-inflammatory or antistenosis agent.

[0024] The embolic protection device of the present invention can alsobe used for embolic protection of other organ systems. For example, anembolic protection device can be deployed in the patient's descendingaorta for preventing embolic particles in the aortic blood flow fromentering the renal arteries and embolizing in the patient's kidneys.

[0025] While the present invention has been described herein withrespect to the exemplary embodiments and the best mode for practicingthe invention, it will be apparent to one of ordinary skill in the artthat many modifications, improvements and subcombinations of the variousembodiments, adaptations and variations can be made to the inventionwithout departing from the spirit and scope thereof.

What is claimed is:
 1. An embolic protection device for deploymentwithin a patient's aorta comprising: an expandable tubular structurecomprising a filter mesh material, the tubular structure having acompressed position, wherein the tubular structure is compressed to asmall diameter for insertion into the patient's aorta, and an expandedposition, wherein the tubular structure expands to a larger diameterthat conforms to an inner wall of the patient's aorta, wherein, when thetubular structure is in the expanded position, the filter mesh materialallows blood to enter sidebranch vessels connected to the patient'saorta, but prevents embolic material from entering the sidebranchvessels.
 2. The embolic protection device of claim 1, wherein theexpandable tubular structure is woven of resilient wires and/or fibersto form a tubular filter mesh.
 3. The embolic protection device of claim1, wherein the filter mesh material is in a tubular configuration. 4.The embolic protection device of claim 1, wherein a panel of filter meshmaterial is supported by the self-expanding tubular structure.
 5. Theembolic protection device of claim 1, wherein the filter mesh materialis configured with waves or undulations.
 6. The embolic protectiondevice of claim 1, wherein the filter mesh material is configured withan inner layer of filter mesh and an outer layer of filter mesh.
 7. Theembolic protection device of claim 6, wherein the inner layer of filtermesh comprises a coarse mesh material and the outer layer of filter meshcomprises a fine mesh material.
 8. The embolic protection device ofclaim 1, further comprising a delivery tube sized and configured to holdthe tubular structure in its compressed position.
 9. The embolicprotection device of claim 1, further comprising a drawstring encirclingthe tubular structure for selectively compressing the tubular structureto a small diameter for withdrawal from the patient.
 10. The embolicprotection device of claim 1, further comprising a plurality of magnetsattached to the tubular structure and a magnetic retrieval catheter forcollapsing the tubular structure and withdrawing the embolic protectiondevice from the patient.
 11. The embolic protection device of claim 1,further comprising an inflatable toroidal balloon for supporting theexpandable tubular structure.
 12. The embolic protection device of claim1, further comprising one or more wire hoops for supporting theexpandable tubular structure.
 13. A method of providing embolicprotection for sidebranch vessels connected to a patient's aortacomprising: introducing an embolic protection device into the patient'saorta, the embolic protection device comprising an expandable tubularstructure supporting a filter mesh material, the tubular structurehaving a compressed position, wherein the tubular structure iscompressed to a small diameter for insertion into the patient's aorta,and an expanded position, wherein the tubular structure expands to alarger diameter that conforms to an inner wall of the patient's aorta;expanding the tubular structure within the patient's aorta such that thefilter mesh material allows blood to enter the sidebranch vesselsconnected to the patient's aorta, but prevents embolic material fromentering the sidebranch vessels.
 14. The method of claim 13, wherein thefilter mesh material is configured with waves or undulations.
 15. Themethod of claim 13, wherein the filter mesh material is configured withan inner layer of filter mesh and an outer layer of filter mesh.
 16. Themethod of claim 15, wherein the inner layer of filter mesh comprises acoarse mesh material and the outer layer of filter mesh comprises a finemesh material.
 17. The method of claim 13, further comprisingcompressing the embolic protection device into a delivery tube forintroduction of the embolic protection device into the aorta.
 18. Themethod of claim 13, wherein the embolic protection device furthercomprises a drawstring encircling the tubular structure for selectivelycompressing the tubular structure to a small diameter for withdrawalfrom the patient.
 19. The method of claim 13, wherein the embolicprotection device further comprises a plurality of magnets attached tothe tubular structure and a magnetic retrieval catheter for collapsingthe tubular structure and withdrawing the embolic protection device fromthe patient.
 20. The method of claim 13, further comprising performingcardiac surgery or a catheter-based interventional cardiology orelectrophysiology procedure on the patient while the embolic protectiondevice is positioned within the aorta.